Diketahui X Dan Y memenuhi system persamaan { 5 X + 13 Y = 13 } { 3 X + 5 Y = 19 } Tentukan nilai X + Y ?

5x + 13y = 13 | x 3 | 15 x + 39y = 39
3x + 5y = 19 | x 5 | 15 x + 25y = 95
____________ -
14y = 56
y = 56/14 = 4
3x + 5y = 19
3x + 5.4 = 19
3x + 20 = 19
3x = 19 - 20
3x = -1
x = -3

jawab

[tex] \left[\begin{array}{ccc}5&13\\3&5\end{array}\right] \left[\begin{array}{ccc}x\\y\end{array}\right] = \left[\begin{array}{ccc}13\\19\end{array}\right] \\ det\, = \left[\begin{array}{ccc}5&13\\3&5\end{array}\right] =25-39=-14 \\ det\,x=\left[\begin{array}{ccc}13&13\\19&5\end{array}\right] =65-247=-182 \\ det\,y=\left[\begin{array}{ccc}5&13\\3&19\end{array}\right]=95-39=56 \\ x= -182/-14=\,13 \\ y= 56/-14=\,-4 [/tex]